1. Field of the Invention
This invention relates to an alarm apparatus and manufacturing method, and more particularly to an alarm apparatus and manufacturing method for monitoring a plant and sensing occurrence of abnormality in the plant, the plant manufacturing products by processing substrates.
2. Background Art
In the conventional process for monitoring occurrence of abnormality in a plant, typically, an engineer uses a visualization tool to examine the number of defects for each product sheet, detects any abnormalities from the number of defects and the degree of concentration thereof, and reports them. However, such work may miss abnormalities at times. Even if abnormality is detected, its cause is not automatically identified. Hence, even if any abnormality occurs in the plant, there is a time lag of typically half a day to several days until the abnormality is detected on the basis of the trend of product defects and its cause is identified. This time lag has been a significant factor in decreased yield. Furthermore, the work of sensing occurrence of abnormality from the trend of the number of defects and the degree of concentration thereof to identify its cause relies on engineers' sense and experience, and unfortunately depends on engineers' personal ability.
On the other hand, conventionally, apparatuses intended for automatically detecting defects are also proposed (see, e.g., JP 2005-197629A). However, defects typically occur at some frequency even when the manufacturing apparatus is normally operated. When abnormality occurs in the manufacturing apparatus, the degree of occurrence of defects is deteriorated. However, how it is deteriorated depends on the type of abnormality. Hence it is difficult to automatically detect abnormality in the manufacturing apparatus from the inspection result of the product.